The Cancer Registry also had the task of monitoring whether the conditions or environment in which people lived posed a risk of cancer. The monitoring of the cancer risk of people living near nuclear power plants was commissioned by the Finnish Radiation and Nuclear Safety Authority, but otherwise the research was mainly driven by the Cancer Registry’s own research interests and the concerns raised by active citizens. The general public was interested – more than the cancer risks related to their personal lifestyle choices – in real or perceived threats beyond their control, typically the potential cancer risks of their living environment. Although the importance of the living environment as a source of cancer risks is small, the Cancer Registry has done a considerable amount of research on this issue, partly because of the extremely accurate regional registry data available in Finland. As similar prerequisites are generally lacking in other parts of the world, the Cancer Registry’s studies have attracted much international attention. Studies of magnetic field exposure from power lines were repeatedly in the news in the 1990s, and radon from soil featured in the news a little later. Monitoring of the Chernobyl nuclear accident overtook other areas of interest in the 2000s, although its effects were not ultimately reflected in the statistics. The finding was expected, as the much larger fallout from the 1960s nuclear tests had not influences cancer risks in Finland. In addition to the actual studies that led to the publication, the Cancer Registry also carried out rapid surveys to address people’s concerns about the potential cancer risks in their living environment. Together with THL, a sub-regional risk monitoring system was developed, which could check in a few days whether there were too many cancers around a factory, along a polluted river or in any other area of concern. Most of the time, the cancer risk level was normal and people’s concerns were allayed, but sometimes it was necessary to launch more detailed investigations. The contaminated drinking water in Kärkölkä and the Myllypuro landfill exposures came up on two occasions: firstly in publications of weak cancer findings during exposure and later – when people were no longer exposed – in follow-up studies where cancer incidence was no longer present. Not only was the incidence of cancer in their own neighbourhoods of interest to the public, and the regional variation in cancer risk was also important information for researchers, but the Cancer Registry developed mapping software using municipal data, which made it possible to show the latest cancer situation but also to animate trends. The visualisation of cancer incidence was so compelling that the Finnish Cancer Registry’s mapping method was soon used in all countries around the Baltic Sea and in many others, and courses were held at the IARC and IACR symposia, among others. Both epidemiological research and map production based on small area data have dwindled in recent years, as new interpretations of the rules have made it difficult to use base data with small numbers.
